From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9F35C2D0E4 for ; Sat, 21 Nov 2020 01:12:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B6B624124 for ; Sat, 21 Nov 2020 01:12:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="rT5oEdJ4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727149AbgKUBMz (ORCPT ); Fri, 20 Nov 2020 20:12:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:39310 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726255AbgKUBMz (ORCPT ); Fri, 20 Nov 2020 20:12:55 -0500 Received: from paulmck-ThinkPad-P72.home (50-39-104-11.bvtn.or.frontiernet.net [50.39.104.11]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9D05D24101; Sat, 21 Nov 2020 01:12:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605921174; bh=KzFDwcBJhD0pOjqa0425Ms5+L0+225sTe32C3oVRTS0=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=rT5oEdJ4+RmqmzRUk43XHmmeDB/LURwejU25VZVf3igQtNwOMQbJxzIfH3Yref+rj pbG4JGfg9WytGoO1D9Nnb0PbMBFNR6u/iIdBc5s4jkW0hatNS/P6DwAvTNzS7h4NO+ baPDzTILy0tLjbV+tW4R2pG8aUqkkBsDx3PNAsIg= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 72EAA3522A6E; Fri, 20 Nov 2020 17:12:54 -0800 (PST) Date: Fri, 20 Nov 2020 17:12:54 -0800 From: "Paul E. McKenney" To: Steven Rostedt Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, mingo@kernel.org, jiangshanlai@gmail.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org Subject: Re: [PATCH tip/core/rcu 0/5] Provide SRCU polling grace-period interfaces Message-ID: <20201121011254.GS1437@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20201117004017.GA7444@paulmck-ThinkPad-P72> <20201121005809.GA16795@paulmck-ThinkPad-P72> <20201120200553.625ee073@oasis.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201120200553.625ee073@oasis.local.home> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org On Fri, Nov 20, 2020 at 08:05:53PM -0500, Steven Rostedt wrote: > On Fri, 20 Nov 2020 16:58:09 -0800 > "Paul E. McKenney" wrote: > > > OK, maybe no one needs it, but rcutorture does need it, so here > > it is anyway. > > Ah, so there was a use case. I was scratching my head a bit before > reading this ;-) Indeed, the overhead of start_poll_synchronize_srcu() is a killer for some parts of rcutorture, plus those parts don't care if no grace period gets started... Thanx, Paul